Norwich-Ely MCB-OD problems?

[Islineclear3_1]

Somebody posted on another thread about problems with the MCB-OD crossings.

I would be very interested to find out what these are because I haven't heard of any problems with the new OD crossings in East Sussex

 

[LowLevel]

Not a clue in detail unfortunately but 'delays due to a problem at a level crossing - obstacle detector fault' regularly ping on to my phone. They also shouldn't be allowed to install them where they drop ages before stopping trains arrive and prevent people from using them to cross the line and board trains (see Wrenbury and Blankney at Metheringham for examples).

 

[Islineclear3_1]

Not a clue in detail unfortunately but 'delays due to a problem at a level crossing - obstacle detector fault' regularly ping on to my phone. They also shouldn't be allowed to install them where they drop ages before stopping trains arrive and prevent people from using them to cross the line and board trains (see Wrenbury and Blankney at Metheringham for examples).

I sat at Polegate recently and the barriers weren't down for any longer than necessary, or any longer than under the previous local arrangements. And the crossing is heavily used...

 

[LowLevel]

I suspect the signalling sections at Polegate which trigger the crossing are significantly shorter than the ones in the previous examples! I've been sat at Wrenbury literally 5 minutes before the train when the barriers came down for it - and it's a request stop as well.

 

[louis97]

I suspect the signalling sections at Polegate which trigger the crossing are significantly shorter than the ones in the previous examples! I've been sat at Wrenbury literally 5 minutes before the train when the barriers came down for it - and it's a request stop as well.

The obstacle detector level crossings are not controlled by the signalling sections, they are controlled by treadles, these are placed so far back along the track and are activated when a train goes over them. The reason you may have waited longer at Wrenbury compared to Polegate is that at Wrenbury in the up direction (towards Shrewsbury) if the level crossing is not down the train can not arrive into the platform. Therefore if the train ends up stopping in the platform it may seem like the barriers have been down for a while but in fact the train will already have passed the protecting signal for the level crossing. Compared to Polegate where the signal in the up direction is at the end of the platform, so therefore the level crossing does not need to go down to allow a train into the platform.

 

[Tomnick]

I don't, thankfully, have the pleasure of dealing with MCB-OD crossings myself, but the fact that it's an OD crossing shouldn't have any great bearing on the timing of the start of the lowering sequence - in that respect, they're no different to CCTV crossings provided with an auto-lower facility. That's not to say that all's well - from personal observation, it does sometimes seem that they're lowered excessively early, and I've heard in particular that the system doesn't differentiate between stopping and non-stopping trains (where it would be acceptable for a train to run into a platform with the barriers at a crossing some distance beyond still raised).

Are they really inititated by treadles rather than just track circuit occupation? I can see the potential benefit of the former, and the more precise timing that would be possible (unless a track circuit was specially split), but it's not so critical to ensure that a train is detected as it is approaching an AHB (where treadles are provided in addition to the track circuit that starts the sequence).

 

[dk1]

The delays where horrendous on the Ely-Norwich for the first year or so but have now calmed down no end. One of the issues was dirt getting onto the eye from faster trains than on the line they where tested & the nature of the road traffic used in this agricultural area. Covers now automatically protect the lens between activations.

 

[TheEdge]

The delays where horrendous on the Ely-Norwich for the first year or so but have now calmed down no end. One of the issues was dirt getting onto the eye from faster trains than on the line they where tested & the nature of the road traffic used in this agricultural area. Covers now automatically protect the lens between activations.

Yea, this basically. Although they do still seem to suffer the issue of detecting such dangerous things as leaves, snow and even heavy rain (!) and failing...

 

[dk1]

Yea, this basically. Although they do still seem to suffer the issue of detecting such dangerous things as leaves, snow and even heavy rain (!) and failing...

The barriers going up & down like a certain ladies draws as they attempt to obtain detection can confuse both us & motorists alike

 

[Islineclear3_1]

The barriers going up & down like a certain ladies draws as they attempt to obtain detection can confuse both us & motorists alike

That might explain why I saw the barriers go down at Polegate on one occasion without a train, only for them to be raised.

But as far as I'm aware, there are covers on the LiDAR....

 

[Class 170101]

Most of the problems for the MCB ODs seem to stem from the LiDAR. I understand from reading that NR turned them off for a period of time and performance improved but NR recived an enforcement notice from the ORR for such move.

 

[LowLevel]

The obstacle detector level crossings are not controlled by the signalling sections, they are controlled by treadles, these are placed so far back along the track and are activated when a train goes over them. The reason you may have waited longer at Wrenbury compared to Polegate is that at Wrenbury in the up direction (towards Shrewsbury) if the level crossing is not down the train can not arrive into the platform. Therefore if the train ends up stopping in the platform it may seem like the barriers have been down for a while but in fact the train will already have passed the protecting signal for the level crossing. Compared to Polegate where the signal in the up direction is at the end of the platform, so therefore the level crossing does not need to go down to allow a train into the platform.

It was on the down line at the time at Wrenbury. If it's a treadle it's extraordinarily far out. Trapping people on the other side of the line from their train is not really on, particularly 5 minutes in advance - it wasn't a problem when a man in a wooden shed next to it controlled the barriers and the same applies at Metheringham.

 

[jopsuk]

It was on the down line at the time at Wrenbury. If it's a treadle it's extraordinarily far out. Trapping people on the other side of the line from their train is not really on, particularly 5 minutes in advance - it wasn't a problem when a man in a wooden shed next to it controlled the barriers and the same applies at Metheringham.

Quite often happens south of Cambridge at Shelford (which has a CCTV crossing)